Biocidal fuel compositions

ABSTRACT

BIOCIDAL FUEL COMPOSITIONS HAVE BEEN DICLOSED WHICH COMPRISE A LIQUID HYDROCARBON FUEL CONTAINING A BIOCIDALLY EFFECTIVE AMOUNT OF SELECTED AMINE SALTS OF 2-MERCAPTOPYRIDINE-1-OXIDE.

United States Patent 01 fee 3,561,152 BIOCIDAL FUEL COMPOSITIONS RomanW. Kulow, Cheshire, Conn., assignor to Olin Corporation, a corporationof Virginia No Drawing. Filed Mar. 4, 1968, Ser. No. 709,958 Int. Cl.C101 1/24 US. Cl. 44-63 8 Claims ABSTRACT OF THE DISCLOSURE Biocidalfuel compositions have been disclosed which comprise a liquidhydrocarbon fuel containing a biocidal- 1y effective amount of selectedamine salts of Z-mercaptopyridine-l-oxide.

This invention relates to biocidal fuel compositions, and moreparticularly, to fuel compositions containing selected amine salts ofZ-mercaptopyridine-l-oxide.

It is known that microorganisms subsist in fuel systems, contributing toa variety of problems with respect to both storage and use of the fuel.Thus, microorganisms emulsify fuel and water forming slimes, generallyat the fuel- Water interface, which interfere with subsequent use of thefuel.

While this problem of microbial contamination is found in all fuelsystems, it is particularly acute in aviation fuels, where, as disclosedby J. M. Sharpley in Elementary Petroleum Microbiology, Gulf PublishingCo., Houston, Tex. (1966) pp. 58-62, the fungus Cladosporium resinae isthe niost prevalent microorganism. It is readily apparent that sli-mesin aviation fuels will plug filters and other equipment, therebyincreasing maintenance expenditures and jeopardizing normal aircraftoperations.

3 Exclusion of moisture from fuel systems is impractical, and thusbiocides, i.e., materials which kill microorganisms and/ or inhibittheir growth, must be used. Such biocides must fulfill many criticalrequirements. Thus, in addition to possessing the required biocidalactivity, they must exhibit no deleterious effects on the fuelproperties. Furthermore, they must not corrode storage tanks or fuelsystem equipment.

Now it has been found that fuel compositions containing, as biocidalagents, selected amine salts of Z-mercaptopyridine-l-oxide are effectivein inhibiting growth of microorganisms in fuel systems. The biocidalagents employed in this invention have the formula wherin R is hydrogenor an alkylrnoiety having 1 to 18 carbon atoms and R is an alkyl moietyhaving 3 to 18 carbon atoms.

These amine salts I are readily provided according to the processdescribed in US. Pat. 2,742,393 by reacting an appropriate amine withZ-mercaptopyridine-l-oxide in a substantially anhydrous organic solvent.The reaction is exothermic, and temperatures between about and about 60C. are preferably maintained.

Illustrative amines which can be employed in the preparation of theamine salts I utilized in this invention include primary amines such asisopropylamine, t-butylamine, hexylamine, heptylamine, octylamine,nonylamine, decy-lamine, laurylamine, stearylamine and isomers thereof.Secondary amines such as diisopropylamine, dibutylamine, dioctylamine,n-propyl-t-butylamine, pentylhexyl- 3,561,152 Patented Feb. 9, 1971amine, n-propyllaurylamine, and the like can also be employed herein.

While any compound having the Formula -I can be suitably employed in thepractice of this invention, preferred embodiments utilize those aminesalts -I wherein R is hydrogen and R is alkyl having 3-14 carbon atomsor R is alkyl having 1-6 carbon atoms and R is alkyl having 3-6 carbonatoms.

Any liquid hydrocarbon fuel can be protected against microbialcontamination according to the teaching of this invention.Exemplificative fuels which comprise kerosene-grade petroleum fractionsinclude No. 2 fuel oils as defined in ASTM Tentative SpecificationD-396-64T and aviation turbine fuel as defined in TentativeSpecification D-1655-65T of the ASTM Standards on Petroleum Products.

While the biocidal effect of amine salt I in fuel systems is observedover a wide range of biocide concentration, generally from .1 to about 5p.p.m., and preferably from about .5 to about 2 p.p.m. of the biocide isemployed. Greater and lesser amounts can be utilized, and the ranges setforth herein are not intended to be limiting.

In accordance with the practice of this invention, the biocidal agents Ican be incorporated in fuels in many different ways. Thus, they areadded to the fuel at any point, for example either prior to, during orafter filling of a fuel tank. It is also feasible to supply the biocidesto the fuel in the form of solutions or suspension in a portion of freshfuel. Solvents, diluents, antioxidants and other ingredients can beadvantageously admixed with the biocide prior to incorporation in thefuel system.

The effectiveness of the biocidal fuel compositions of this invention isparticularly surprising and unexpected in view of the ineffectiveness ofvarious other materials derived from Z-mercaptopyridine-l-oxide in thisapplication. Thus, while it is known that 2-mercaptopyridine-1- oxideand its derivatives possess biocidal activity, it has been found thatsuch derivatives as the ammonium salt of Z-mercaptopyridine-l-oxide anddisulfide derivatives such as 2,2'-dithiopyridine-1,1'-dioxide areineffective in inhibiting growth in fuel systems.

The following examples will serve to illustrate the process of thisinvention.

EXAMPLE 1 (A) Preparation of t-butylaminesalt ofZ-mercaptopyridine-l-oxide (B) Preparation and testing of fuelcomposition The t-butylamine salt of Z-mercaptopyridine-l-oxidedescribed in Part A was added in varying amounts to a number of 750 ml.portions of kerosene. Each of the resulting compositions was then mixedin a separatory funnel with 30 ml. of water containing Cladosporiumresinae (10 organisms/ml.). The flasks were stoppered, stored at roomtemperature and shaken several times per day. At intervals, aliquotswere taken from both the kerosene and the aqueous phase of each mixture,streaked on agar and then incubated at 37 C. for 96 hours. At the end ofthe incubation period, the samples were examined and rated 0 forsterility or for growth. The results of the tests are set forth in thetable below.

3 EXAMPLE 2 (A) Preparation of diisopropylamine salt of 2-mercaptopyridined-oxide To a solution of 25.4 g. (0.2 mode) ofZ-mercaptopyridine-l-oxide in 100 ml. of chloroform was added gradually,with stirring, at 10-15 C., 20.2 g. (0.2 mole) of diisopropylamine.After stirring the reaction mixture for one hour, chloroform was removedon a rotary film evaporator, thereby providing 31 g. of thediisopropylamine salt of Z-mercaptopyridine-l-oxide, MP. 94 96 C.

(B) Preparation and testing of fuel compositions Following the procedureof Example 1, compositions were prepared and tested employing thediisopropylamine salt of Z-mercaptopyridine-l-oxide as the biocide. Theresults are set forth in the table below.

EXAMPLE 3 (A) Preparation of laurylamine salt of 2-mercaptopyridine-l-oxide Laurylamine (72.8 g., 0.394 mole) was added,with stirring, in small portions to a slurry of2-mercaptopyridine-l-oxide (50 g., 0.394 mole) in 300 ml. water and 100ml. ethanol at room temperature. When the addition was completed, theresulting solution was filtered and evaporated in a rotary evaporator at70-80 C./2030 mm. Hg to provide a light colored solid. Drying of thesolid product for an additional 16 hours under vacuum yielded 103 g. ofthe laurylamine salt of Z-mercaptopyridine-l-oxide, M.P. 80-81 C.

(B) Preparation and testing of fuel compositions Following the procedureof the previous examples, compositions were prepared and testedemploying the laurylamine salt of 2-mercaptopyridine-1-oxide as thebiocide. The results are set forth in the table below.

COMPARATIVE EXAMPLES 1-3 For purposes of comparison, fuel compositionswere formulated and tested as described in the previous examplesemploying the following bioeides:

C-l: Control (no biocide) C-2: Ammonium salt ofZ-mercaptopyridine-l-oxide (prepared according to US. Pat. 2,686,786,Example 12) C-3: 2,2'-dithiopyridine-1,l-dioxide (prepared according toUS. Pat. 2,742,476, Example 1) TABLE I Concentration Time (days) biocide(p.p.m.) 1 5 7 170 Example:

EXAMPLE 4 The amount of 80 grams of the t-butylamine salt of 2. The fuelcomposition of claim 1 wherein from about tank of JP-4 jet fuelcontaining approximately 250 gallons of water. After 90 days at ambientconditions, no growth is observed.

What is claimed is:

1. A fuel composition which comprises a liquid hydrocarbon fuelcontaining a biocidally effective amount of an amine salt having theformula wherein R is hydrogen or an alkyl moiety having 1 to 18 carbonatoms and R is an alkyl moiety having 3 to 18 carbon atoms.

2. The fuel composition of claim 1 wherein from about 0.1 to about 5ppm. of said amine salt is employed.

3. The fuel composition of claim 1 wherein R is hydrogen and R is analkyl moiety having 3 to 14 carbon atoms.

4. The fuel composition of claim 3 wherein the tbutylbutylamine salt ofZ-mercaptopyridine-l-oxide is employed as the amine salt.

5. The fuel composition of claim 3 wherein the laurylamine salt ofZ-mercaptopyridine-l-oxide is employed as the amine salt.

6. The fuel composition of claim 1 wherein R is an alkyl moiety having 1to 6 carbon atoms and R is an alkyl moiety having 3 to 6 carbon atoms.

7. The fuel composition of claim 6 wherein the diisopropylamine salt of2-mercaptopyridine-l-oxide is employed as the amine salt.

8. A binary system comprising a liquid hydrocarbon fuel and water, saidsystem containing a biocidally effective amount of an amine salt havingthe formula wherein R is hydrogen or an alkyl moiety having 1 to 18carbon atoms and R' is an alkyl moiety having 3 to 18 carbon atoms.

References Cited UNITED STATES PATENTS 2,742,393 4/ 1956 Bernstein et al424-308 2,975,042 3/ 1961 Summers, Jr. 44-78 2,975,043 3/1961 Ambrose44-78 DANIEL E. WYMAN, Primary Examiner Y. H. SMITH, Assistant Examiner

